I just brought home a bunch of live sand for my 20 gallon from the LFS.
The tank at the store where I got it from had a lot of Bubble algae in it. I also got a powerhead from the same tank.
How can I get the bubble algae off the powerhead and will the sand infect my tank?

The sand is probably fine. I guess there could be some spores in it, but I don't think I would worry about it. As for the powerhead, scrape all the bubble algae (and whatever else is on it) off, run it in some water with some white vinegar in it for a couple of hours to clean it up real well, then just rinse it off and put it in the tank.

Thanks. Also I received a really cool piece of some dead coral, which now is kind of like live rock I guess. Half of it is purple and a few tips are also purple, it is some kind of hard coral.
I have a large and small piece. The small has HA and bubble algae all over it, I'm going to toss it. But the large piece only had one small bubble I could see and I removed it, is it safe?

it should be, just rinse it really well to make sure that there are no BA spores left on it before you add it to the tank.

I'd think so, but that stuff can be sneaky. If you're really worried about it, you can always just leave the pieces out in the sun for a week or two. They won't be live anymore, but they'll come back to life quickly in a tank with live rock and sand. If you like the pieces, there;s no need to ditch them.

Thanks. I have no RO/DI water filtration system, is it okay to rinse with tap water?
I get my water from a LFS and won't be able to get any.
What if I clean it out really well in the bucket of water?
Will all this sand speed up my cycle?

Tap should be fine for this. Mixing in vinegar will help remove any calcium buildup, and will help kill any nasties on the powerhead.

Live sand should increase the bacterial count, which should speed up the cycle slightly.

Okay. I cleaned the powerhead and it is in a bucket of water and vinegar now. The sand is really making the water gross. So you mean I can clean it with tap?

Clean which? It's fine to clean the powerhead with tap water.

if you DO happen to get a few bubble spores in the tank after every precaution ... you can always add a couple of emerald crabs to the tank and they usually take care of it.

Okay thanks.
I plan on adding emeralds, peppermint shrimp, and hermits as bubble and hair algae and aiptasia prevention.

Just to clarify, it is OK to use tap water to clean equipment. It is not OK to use it in your tank. If the LFS is closing I would check Wal-mart to see if they have a water machine that people refill their 5 gallon jugs from. Although this is only RO and not DI it is far safer than using tap water. Don't stress too much about the gross water form the sand. It will clear up.

I the local supermarket has a machine that says it produces RO/DI water.

Good deal! This is far better than tap or well water.

Could well be. A couple of grocery stores near me have RO machines for filling water bottles. No DI though...

The Whole Foods nearest to us has both RO and RO/DI.

That's convenient, although why anyone would want to drink RO/DI is beyond me...

It does taste really flat.